Process for the manufacture of an amino ester of formula (I) R1—O—C(O)—(CH2)n—NH2 (I) in which n is an integer from 10 to 15 from an unsaturated ester responding to formula (II) R1—O—C(O)—(CH2)m—CH═CH—R2 (II) in which R1 is either H or a saturated alkyl group containing from 1 to 5 carbon atoms; R2 is either H or an alkyl group containing from 1 to 10 carbon atoms, either saturated or containing 1 or 2 unsaturations and bearing optionally a hydroxyl, a carboxylic or an ester group, and m is equal to 7, 8, 9, 10 or 11; said process comprising: submitting the unsaturated ester of formula (II) to a catalytic cross-metathesis reaction with a pentenenitrile chosen among 2-pentenenitrile or 3-pentenenitrile in order to obtain a ester-nitrile responding to formula (III) R1—O—C(O)—(CH2)m—CH═CH—(CH2)p—CN (III) in which m is equal to 7, 8, 9, 10 or 11 and p is equal to 0 or 1, and submitting the obtained ester-nitrile of formula (III) to an hydrogenation in order to obtain the amino ester of formula (I).